Graphite seals operating at high circumferential velocity are often accompanied by high heat frictional wear,in order to meet the sealing requirements of high circumferential velocity and low-pressure differential conditions,multiple physical coupling model was established based on the four segments graphite seal.The accuracy of the calculation model was verified by comparing the calculated results with the experimental results.Based on the multi physical field coupling analysis,the coupling characteristics of flow field,temperature field and structural field of high velocity graphite seals under high circumferential velocity and low-pressure differential conditions were studied.The results show that the pressure of the sealing gas at the circumferential groove and the lap of the sealing ring is unbalanced,the velocity distribution is uneven and the flow field is disordered near the outlet.The leakage amount decreases with the increase of seal circumferential velocity and increases with the increase of seal pressure difference.The temperature,deformation and stress of the seal ring increase with the increase of the seal circumferential velocity.The temperature field has the greatest influence on the structure of the seal ring.The sealing gas can alleviate the deformation of the seal ring,but the gas force will increase the stress value of the seal ring.The friction heat has a significant effect on the sealing structure,the lap joint of ring section and anti-rotation pin are the weakest links of seal ring.